This choropleth map visualizes geographic regions using color-coded areas, with countries filled in light green and strokes in black at low opacity. The visualization employs a blue sphere to represent the globe, set against a clean white background. Built with D3 v5, the code uses `select` to target the SVG element and `json` to load geographic data from the OneMap service, while the `topojson` library’s `feature` function processes the topology. The map is rendered as an SVG with a fixed 960x500 viewport, with styling defined in CSS.